消除485总线噪声影响的应用一例

就一实例说明如何通过软件设计的方法来消除系统中存在的各种噪声,保证系统的正常运行。     

Palmprint based recognition system using phase-difference information

This paper presents an efficient palmprint based human recognition system. Each palmprint is divided into several square overlapping blocks. Reconstruction error using principle component analysis (PCA) is used to classify these blocks into either a good block or a non-palmprint block. Features from each good block of a palmprint are obtained by binarising the phase-difference of vertical and horizontal phase. The Hamming distance is used to compute the matching score between the features of corresponding good blocks of enrolled and live palmprint. These matching scores are fused using weighted sum rule, where weights are based on the average discriminating level of a block relative to other blocks. The performance of the proposed system is analysed on different datasets of hand images and it has been observed that it achieves a Correct Recognition Rate of 100% with a low Equal Error Rate for all the datasets. The system is also evaluated for noisy and bad palmprint images. It is found to be robust as long as the noise density is less than 50% or the bad region is less than 64% of the images.     

柴窝堡二维地震资料目标处理方法研究应用

柴窝堡地区地震资料采集于上世纪八十年代,受当时技术条件限制,老资料能量弱,覆盖次数低,导致处理成果信噪比低,难以满足解释要求。在重新处理过程中,通过对地震地质资料特点的全面分析,针对处理目标从静校正、噪音衰减、精细速度分析到偏移制定了一系列有针对性的处理方法,通过应用实施取得了很好的效果。     

基于最小噪声分离变换的高光谱异常检测方法研究

RX算法和核RX算法能很好地分离目标和背景,是较为广泛使用的异常检测算法,但是高光谱图像数据量大且存在冗余信息和噪声,直接进行RX及核RX异常探测运算量大且容易受噪声影响.针对此问题,提出一种基于最小噪声分离变换的高光谱图像异常检测方法,首先采用残差分析法估计噪声协方差矩阵以改进最小噪声分离变换,然后利用改进后的最小噪声分离变换来有效地降低高光谱图像数据的维数并分离出噪声,最后对低维降噪后的数据进行RX及核RX异常检测,避免了随机噪声对RX及核RX异常检测结果的影响并提高了异常检测率.对真实的AVIRIS数据测试表明,该算法优于传统的相应的RX、核RX异常检测算法.     

瑞利信道下线性分组码的分集增益研究

比较AWGN信道与瑞利信道的误码性能,研究瑞利信道下分集支数与信息传输可靠性之间的关系。推导线性分组码在瑞利信道下误码率上界的理论表达式,得到分集增益与其最小汉明距离的关系。基于蒙特卡洛法对误码性能进行仿真,并与理论误码率上界进行比较,结果表明线性分组码在瑞利信道下获得的分集增益等于其最小码距。     

大型空分设备气体放空的噪声控制与治理

文章简介了空分设备气体放空时产生的噪声对周围环境的污染和伤害,并对放空气体噪声的控制与治理进行了分析对比;提出大型空分设备,特别是内压缩流程的空分设备,大流量低、中、高压气体放空,应采用消声塔集中排放,有效控制和治理气体放空噪声。     

高噪声条件下基于投影的二维条码倾斜检测

图像倾斜纠正是二维条码自动识别过程中的重要步骤,最常用的倾斜角检测方法是基于Hough变化的方法,实际应用中Hough变换峰值扩散效应显著,同时在速度上也难以适应实时应用的需求。提出使用投影法对倾斜的二维条码图像进行倾斜角判断,并通过加速策略提高检测速度,能够在高噪声条件下快速得到精确的结果。     

一种改进的金相图像处理自适应加权均值滤波方法

金相组织图像分析是显微图像分析中的一个重要内容。由于噪声的存在会对图像分析带来很大的误差,因此进行图像分析前需要对金相图像进行滤噪处理,从而使图像的细节更加突出,便于目标识别。针对标准均值滤波方法存在的不足,提出自适应加权均值滤波方法。该方法通过检测确定图像中的脉冲噪声点,并用改进的均值滤波方法对检测出的噪声点进行滤波。实验结果表明,自适应加权均值滤波能在有效地去除噪声的同时,较好地保护图像细节,较标准均值滤波具有更优良的滤波效果,而且可与更大窗口的中值滤波效果相媲美,其处理速度比大窗口的中值滤波快。     

直流开关电源传导型噪声分析

传导型噪声是开关电源的主要骚扰源,它可以通过电源线、信号线、互连线、接地导体等进行耦合.其类型有输入端噪声和超高频输出噪声.其中输入端噪声有共模和差模2种噪声.由于传导型噪声会降低直流开关电源的性能,严重时会造成直流开关电源的损坏.因此,分析其传导型噪声,并采取相应防范措施,具有现实意义.详细分析了传导型噪声产生的原因,并分析了传导型噪声模型,给出了应采取的措施.     

Stiffness-Damping Simultaneous Identification under Limited Observation

A more reliable and stable method, compared to the previous one developed by the present writers, of stiffness-damping simultaneous identification of shear-type building structures is proposed using stationary random records under limited observation. It is shown that when stationary random horizontal accelerations are recorded at the floors just above and below a specific story in a shear building model, the story stiffness and the damping ratio can be identified uniquely. The viscous damping coefficient and the material damping ratio can also be identified simultaneously in a numerical model structure. It is also shown that unfavorable effects by extraneous noises, including measurement noises, due to wind excitation, building facilities, and the motion of the occupants can be eliminated partially by using the present method. The accuracy of the present identification method is investigated through the actual records under limited observation in a base-isolated building.